So-called alcohol interlock systems are known from the state of the art, which are used to prevent a driver who is under the influence of alcohol following a positive alcohol measurement from starting the engine of a motor vehicle (passenger car, truck, bus, etc.), from operating a machine or from entering a secured area in a company. Such an alcohol interlock system contains essentially an alcohol-measuring device, which is installed, as a rule, permanently in the interior of the vehicle, as well as a control device, which is coupled to the alcohol-measuring device and which is installed permanently, for example, under the instrument panel of the vehicle and is designed to release or block the power supply to the starter of the vehicle. The alcohol-measuring device is preferably a breath alcohol-measuring device, which is designed as a hand-held device and is connected to the control device via an electric connection cable.
These prior-art alcohol interlock systems are also in use in large numbers in so-called offender programs, in which persons are only permitted to drive a vehicle under the condition that they allow such a system to be installed in their vehicle. These conditions are, in general, subject to a time limitation, and the systems are removed from the vehicle after the end of that period. Alcohol interlock systems thus represent a cost-effective alternative to a possible prison sentence or (in most cases) to the revocation of the driver's license to the state and also for the driver, who is sentenced, for example, because of drunkenness. Since the drivers who have been sentenced usually have to install an alcohol interlock system for a limited time period only, such systems are usually leased to the drivers in these so-called offer programs. Consequently, only the costs for the lease payment and possibly costs for the special mouthpieces are incurred.
Methods for determining substances in body fluids are known as well. The corresponding detection methods comprise chemical, biochemical, electrochemical and optical methods. For example, the specific reaction of cannabinoids with Gibbs reagent, which can be detected either directly by color reaction or indirectly by electrochemical detection, is known (Studies on Hashish. IV Colour reactions of Cannabinols, Qual. Plant. Mater. Veg. XXII: 7-13, 1972). The direct electrochemical detection of cannabis preferably following chromatographic separation of the components of the sample has been described as well (Analysis of Cannabinoids, Research Monographs 42, NIDA, 1982). The optical properties of common drugs are described together with a review of measuring techniques, e.g., in the study of zlem Baran: “Determination of narcotic and psychotropic substances by using infrared spectroscopy,” Middle East Technical University, July 2005 (http:/etd.metu.edu.tr/upload/12606293/index.pdf). Especially immunochemical methods are used for the trace analysis of medicinal drugs or illegal drugs from body fluids, for example, blood, urine, sweat or saliva.
When collecting body fluids, it is rather important to collect and make available a sufficient quantity or a sufficient volume of body fluid for the necessary analysis. For example, when drawing blood, the quantity of blood drawn can be checked easily by means of the scale of the syringe or, when urine is used, by means of the scale on the measuring vessel. In case of tests based on saliva, the filling level can be displayed, e.g., by a color change of the sampler when a desired quantity is reached. The decision on whether or not a sufficient quantity of body fluid is available is not made by the person to be tested but by the person (for example, a physician), who performs the test. For comparison, the volume measurement is performed by a gas flow sensor in the device in case of breath alcohol-measuring devices.
The above methods are used as rapid tests for the occupational medical monitoring of persons at hazardous workplaces or even for testing automobile drivers during roadside checks.
As is described in the “NHTSA Report DOT HS 811 249 2007 National Roadside Survey of Alcohol and Drug Use by Drivers: Drug Results,” the consumption of drugs is also a frequently occurring offence during the operation of motor vehicles, besides the consumption of alcohol. It is therefore desirable, in principle, to test vehicle drivers not only for alcohol consumption, but also for the consumption of drugs, and to prevent a vehicle from being started in case of drug consumption.
An alcohol interlock device, which carries out an alcohol test on the basis of a saliva sample, is known from WO 2009/083964 A2. The giving of a sufficient quantity of saliva is either assumed as given by a person for a sample holder inserted into the mouth after the end of a certain time or read on the basis of the filling level of a capillary receiving the saliva. The interlock device may also be modified in order to test the saliva for drugs. This interlock device has the drawback that errors of measurement may occur when a measurement is carried out with an insufficient quantity of saliva, because this could cause a lower alcohol concentration to be measured than is actually present in the body.
There also is, in principle, a possibility of tampering with all prior-art interlock systems due, for example, to a sample requested by the system being given by a second person, who is not the person who is to be tested. In order to eliminate such a possibility of circumvention, prior-art alcohol interlock systems usually have an alcohol measurement repeat function. This means that the interlock system prompts the driver again after a randomly generated interval of time to perform an alcohol measurement. Tampering shall be made at least difficult in this manner.
DE 197 42 261 A1 describes a device for blocking the operation of a vehicle by a driver who is under the influence of alcohol. The alcohol-measuring device is designed to be attached to a body part (arm or leg) of the driver and to be able to measure the driver's alcohol level by means of an electrochemical gas sensor on the basis skin permeation. The analyzing unit proper of the device, via which the vehicle is released or blocked, is mounted permanently in the vehicle and communicates with the measuring device in a wireless manner.
U.S. Pat. No. 7,256,700 B1 pertains to an interlock system, by means of which a vehicle is prevented from being started by a driver who is under the influence of alcohol. The interlock system is coupled to a mobile telephone or a similar communications means, with which a failed alcohol measurement is communicated by a voice message being sent via the mobile telephone. Furthermore, data, which are stored in the interlock system, can also be sent over the mobile telephone.
US 2007/0273537 A1 discloses a combined testing and localization system, which contains, among other things, an interlock system. The interlock system is used in the known manner to prevent a vehicle from being started by a driver who is under the influence of alcohol. The system is equipped, furthermore, with an EMHA system (Electronic Monitoring Home Arrest), which can communicate with a remote server, for example, via a mobile telephone. However, data being stored in the interlock system can also be transmitted to the server via this mobile telephone.
US 2006/0173256 A1 pertains to an interlock system to prevent a vehicle or a machine from being operated by a person who is under the influence of alcohol. Methods and devices for the noninvasive measurement of alcohol and other substances are used for this.
Many of the events relevant for the use, for example, data, time, the giving of a sample, values measured for the sample, engine starts and stops, as well as attempts at tampering with the interlock system, can be recorded in a memory of the interlock system during the use of the vehicle. These data can be compiled into a protocol and read, for example, by means of a data cable. The reading may be carried out, for example, in an authorized workshop or on site by an authorized mechanic.
One drawback of the prior-art interlock systems is that they cannot be deactivated or reactivated from a remote center. Should, for example, the vehicle be prevented from being started because of a technical defect of the interlock system or based on a malfunction of the detection system, the driver is consequently unable to start his vehicle without the aid of another person. The defective interlock system can be released or deactivated in such a case on site only at the interlock system of the vehicle itself by an authorized mechanic entering a secret release code into the interlock system, for example, by means of a computer, which is connected to a corresponding interface of the interlock system via a data cable, as a result of which the interlock system is released or deactivated and the engine of the vehicle can again be started. As an alternative, the interlock system must be repaired and reactivated in a workshop.